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3 February 2009 Horizontally scanning holography to enlarge both image size and viewing zone angle
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In order to enlarge the image size and viewing zone angle of a hologram, an image generated by a high-speed spatial light modulator (SLM) is converted into a vertically long image by an anamorphic imaging system, and this image is scanned horizontally by a galvano scanner. The reduction of the horizontal pixel pitch of the SLM provides a wide viewing zone angle. The increase of the image height and horizontal scan enlarge the image size. In this study, a digital micromirror device (DMD) with the resolution of 1,024×768 was used as a high-speed SLM. A laser diode with the wavelength of 635 nm was used as a light source. An anamorphic imaging system had the magnifications of 0.183 and 5.0 in the horizontal and vertical directions, respectively, to generate a vertically long image with the size of 2.56 mm×52.5 mm. The horizontal pixel pitch was reduced to 2.5 μm to provide the horizontal viewing zone angle of 15°. The horizontal scan width of the galvano scanner was 73.1 mm, so the resultant image size was 73.1 mm×52.5 mm. The scanning frequency of the galvano scanner was 60 Hz and the frame rate of the DMD was 13.333 kHz so that one hologram consisted of 222 vertically long images. The vertically long images were displayed with the horizontal pitch of 0.32 mm and there were substantial overlaps. We succeeded the generation of a hologram image having 15° horizontal viewing zone angle and 3.5" screen size with a 60 Hz frame rate.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Naoya Okada and Yasuhiro Takaki "Horizontally scanning holography to enlarge both image size and viewing zone angle", Proc. SPIE 7233, Practical Holography XXIII: Materials and Applications, 723309 (3 February 2009);

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